Maize hybrid variety ICH72121

ABSTRACT

Disclosed herein are seed and plants of the maize hybrid variety designated ICH72121, as well as cells and cell cultures derived therefrom. Further disclosed are methods for producing seed, commodity products, and derived progeny plants from the maize hybrid variety designated ICH72121.

CROSS-REFERENCE TO RELATED APPLICATIONS

This U.S. non-provisional patent application claims the benefit of U.S.Provisional Patent Application No. 63/004,099, filed Apr. 2, 2020.

FIELD

Aspects of this disclosure relate generally to the field of maizebreeding, in particular to seed and plants of the maize hybrid varietydesignated ICH72121, representative seed of which having been depositedunder ATCC Accession number PTA-126952. Further aspects of thedisclosure relate to plant cells, plant parts, tissue cultures, andplants produced from the seed of the maize hybrid variety ICH72121.Still further aspects of the disclosure relate to progeny, variants,mutants, and minor modifications of the maize hybrid variety ICH72121.Additional aspects of this disclosure are related to methods forproducing maize plants comprising crossing the maize hybrid varietyICH72121 with itself or with another maize plant, as well as methods forproducing a maize plant characterized by one or more specific traitsintroduced or introgressed into the maize hybrid variety ICH72121 (e.g.,by backcross conversion, transformation, genome editing, and/orepigenetic modification).

BACKGROUND

It is the goal of maize breeders to combine multiple desirable traits(e.g., improvements in yield, pest or disease resistance, tolerance toabiotic stress, nutritional qualities, and agronomic qualities) in asingle maize inbred or hybrid variety. To create an inbred maizevariety, breeders self-pollinate maize plants, evaluate the resultingprogeny, and select for the desired phenotype, repeating this processover many generations in order to produce an inbred maize line that ishighly homozygous (homozygous at many or almost all gene loci) and thatproduces uniform progeny. Crossing two different inbred maize parentsproduces first generation (“F₁”) hybrid maize plants that areheterozygous at many gene loci, phenotypically uniform, and oftensuperior in performance in comparison to one or both inbred parents.Maize breeders aim to develop both superior inbred parent maize lines aswell as superior maize hybrid varieties based on crosses of inbred maizelines.

SUMMARY

Disclosed herein are novel maize hybrid varieties, including the maizevariety designated ICH72121, representative seed of which having beendeposited under ATCC Accession number PTA-126952.

Each of the novel maize hybrid varieties described in this disclosurecan be arrived at through crossing of inbred parent maize lines orthrough selection of the desirable characteristics (e.g., as detailed inthe Tables of this disclosure) by using any breeding and selectionmethod deemed appropriate by the maize breeder. In embodiments, themaize hybrid variety ICH72121 is made by crossing female parent inbredline RR728-18 (ATCC Accession number PTA-5628; disclosed in U.S. Pat.No. 6,677,509, which is incorporated herein by reference in itsentirety) with male parent line PHBE2 (ATCC Accession number 97509,disclosed in U.S. Pat. No. 5,563,325, which is incorporated herein byreference in its entirety), as detailed below. Further embodimentsinclude a maize plant having essentially all the physiological andmorphological characteristics of the maize hybrid variety ICH72121, andfurther characterized by having at least one additional trait, e.g., anagronomically or economically useful trait such as increased toleranceof biotic or abiotic stress, resistance to herbicides commonly used incommercial production of maize, male sterility, and modified nutritionalcontent.

Other aspects of this disclosure are related to seeds, plant parts,tissues, callus, and tissue cultures of the maize hybrid varietyICH72121, maize plantlets or plants regenerated or grown therefrom, andprogeny plants and seeds derived from these or directly from the maizehybrid variety ICH72121. Additional aspects of this disclosure arerelated to methods of producing a maize plant derived from the maizehybrid variety ICH72121, for example by backcrossing, genetictransformation to introduce a transgene, or editing of the genome at apredetermined location with a sequence-specific nuclease. Yet otheraspects of the disclosure are related to seed of the maize hybridvariety ICH72121 or of their progeny or derived plants, and commodityproducts produced from these seeds or from the plants themselves. Alsodisclosed are methods of producing nucleic acid preparations from theseed or a maize plant of the maize hybrid variety ICH72121 or of theirprogeny or derived plants, obtaining genomic or genetic information fromthe nucleic acid preparations, and using the information thus obtainedin maize breeding.

DETAILED DESCRIPTION OF THE INVENTION Definitions of PlantCharacteristics

Barren Plants: Plants that are barren, i.e., lack an ear with grain, orhave an ear with only a few scattered kernels.

Cg: Colletotrichum graminicola rating. The rating multiplied by 10 isapproximately equal to percent total plant infection.

CLN: Maize Lethal Necrosis (combination of Maize Chlorotic Mottle Virusand Maize Dwarf Mosaic virus) rating. A numerical rating that is basedon a 1 to 9 scale of severity in which “1” indicates “most resistant”and “9” indicates “most susceptible”.

Cn: Corynebacterium nebraskense rating. The rating multiplied by 10 isapproximately equal to percent total plant infection.

Cz: Cercospora zeae-maydis rating. The rating multiplied by 10 isapproximately equal to percent total plant infection.

Dgg: Diatraea grandiosella girdling rating. A rating in which the valueequals percent plants girdled and stalk lodged.

Dropped Ears: Ears that have fallen from the plant to the ground.

Dsp: Diabrotica species root rating. A rating that is based on a 1 to 9scale in which “1” indicates “least affected” and “9” indicates “severepruning”.

Ear-Attitude: The attitude or position of the ear at harvest, which isscored as upright, horizontal, or pendant.

Ear-Cob Color: The color of the cob, which is scored as white, pink,red, or brown.

Ear-Cob Diameter: The average diameter of the cob when measured at themidpoint.

Ear-Cob Strength: A measure of mechanical strength of the cobs tobreakage, which is scored as strong or weak.

Ear-Diameter: The average diameter of the ear when measured at themidpoint.

Ear-Dry Husk Color: The color of the husks at harvest, which is scoredas buff, red, or purple.

Ear-Fresh Husk Color: The color of the husks 1 to 2 weeks afterpollination, which is scored as green, red, or purple.

Ear-Husk Bract: The length of an average husk leaf, which is scored asshort, medium, or long.

Ear-Husk Cover: The average distance from the tip of the ear to the tipof the husks in which the minimum value is no less than zero.

Ear-Husk Opening: An evaluation of husk tightness at harvest, which isscored as tight, intermediate, or open.

Ear-Length: The average length of the ear.

Ear-Number Per Stalk: The average number of ears per plant.

Ear-Shank Internodes: The average number of internodes on the ear shank.

Ear-Shank Length: The average length of the ear shank.

Ear-Shelling Percent: The average of the shelled grain weight divided bythe sum of the shelled grain weight and cob weight for a single ear.

Ear-Silk Color: The color of the silk observed 2 to 3 days after silkemergence, which is scored as green-yellow, yellow, pink, red, orpurple.

Ear-Taper (Shape): The taper or shape of the ear, which is scored asconical, semi-conical, or cylindrical.

Ear-Weight: The average weight of an ear.

Early Stand: The percent of plants that emerge from the ground asdetermined in the early spring.

ER: Ear rot rating. A rating in which the value approximates percent earrotted.

Final Stand Count: The number of plants just prior to harvest.

GDUs: Growing degree units. GDUs are calculated by the Barger Method inwhich the heat units for a 24-hour period are calculated as follows:[(Maximum daily temperature+Minimum daily temperature)/2]−50. Thehighest maximum daily temperature used is 86 degrees Fahrenheit. and thelowest minimum temperature used is 50 degrees Fahrenheit.

GDUs to Shed: The number of growing degree units (GDUs) or heat unitsrequired for a variety to have approximately 50% of the plants sheddingpollen as measured from time of planting. GDUs to shed is determined bysumming the individual GDU daily values from the planting date to thedate of 50% pollen shed.

GDUs to Silk: The number of growing degree units (GDUs) for a variety tohave approximately 50% of the plants with silk emergence as measuredfrom the time of planting. GDUs to silk is determined by summing theindividual GDU daily values from the planting date to the date of 50%silking.

Hc2: Helminthosporium carbonum race 2 rating. The rating multiplied by10 is approximately equal to percent total plant infection.

Hc3: Helminthosporium carbonum race 3 rating. The rating multiplied by10 is approximately equal to percent total plant infection.

Hm: Helminthosporium maydis race 0 rating. The rating multiplied by 10is approximately equal to percent total plant infection.

Ht1: Helminthosporium turcicum race 1 rating. The rating multiplied by10 is approximately equal to percent total plant infection.

Ht2: Helminthosporium turcicum race 2 rating. The rating multiplied by10 is approximately equal to percent total plant infection.

HtG: Chlorotic-lesion type resistance. “+” indicates the presence of Htchlorotic-lesion type resistance; “−” indicates absence of Htchlorotic-lesion type resistance; and “+/−” indicates segregation of Htchlorotic-lesion type resistance. The rating multiplied by 10 isapproximately equal to percent total plant infection.

Kernel-Aleurone Color: The color of the aleurone, which is scored aswhite, pink, tan, brown, bronze, red, purple, pale purple, colorless, orvariegated.

Kernel-Cap Color: The color of the kernel cap observed at dry stage,which is scored as white, lemon-yellow, yellow, or orange.

Kernel-Endosperm Color: The color of the endosperm, which is scored aswhite, pale yellow, or yellow.

Kernel-Endosperm Type: The type of endosperm, which is scored as normal,waxy, or opaque.

Kernel-Grade: The percent of kernels that are classified as rounds.

Kernel-Length: The average distance from the cap of the kernel to thepedicel.

Kernel-Number Per Row: The average number of kernels in a single row.

Kernel-Pericarp Color: The color of the pericarp, which is scored ascolorless, red-white crown, tan, bronze, brown, light red, cherry red,or variegated.

Kernel-Row Direction: The direction of the kernel rows on the ear, whichis scored as straight, slightly curved, spiral, or indistinct(scattered).

Kernel-Row Number: The average number of rows of kernels on a singleear.

Kernel-Side Color: The color of the kernel side observed at the drystage, which is scored as white, pale yellow, yellow, orange, red, orbrown.

Kernel-Thickness: The distance across the narrow side of the kernel.

Kernel-Type: The type of kernel, which is scored as dent, flint, orintermediate.

Kernel-Weight: The average weight of a predetermined number of kernels.

Kernel-Width: The distance across the flat side of the kernel.

Kz: Kabatiella zeae rating. The rating multiplied by 10 is approximatelyequal to percent total plant infection.

Leaf-Angle: Angle of the upper leaves to the stalk, which is scored asupright (0 to 30 degrees), intermediate (30 to 60 degrees), or lax (60to 90 degrees).

Leaf-Color: The color of the leaves 1 to 2 weeks after pollination,which is scored as light green, medium green, dark green, or very darkgreen.

Leaf-Length: The average length of the primary ear leaf.

Leaf-Longitudinal Creases: A rating of the number of longitudinalcreases on the leaf surface 1 to 2 weeks after pollination. Creases arescored as absent, few, or many.

Leaf-Marginal Waves: A rating of the waviness of the leaf margin 1 to 2weeks after pollination, which is rated as none, few, or many.

Leaf-Number: The average number of leaves of a mature plant. Countingbegins with the cotyledonary leaf and ends with the flag leaf.

Leaf-Sheath Anthocyanin: A rating of the level of anthocyanin in theleaf sheath 1 to 2 weeks after pollination, which is scored as absent,basal-weak, basal-strong, weak, or strong.

Leaf-Sheath Pubescence: A rating of the pubescence of the leaf sheath.Ratings are taken 1 to 2 weeks after pollination and scored as light,medium, or heavy.

Leaf-Width: The average width of the primary ear leaf when measured atits widest point.

LSS: Late season standability. The value multiplied by 10 isapproximately equal to percent plants lodged in disease evaluationplots.

Moisture: The moisture of the grain at harvest.

On1: Ostrinia nubilalis 1st brood rating. The rating is based on a 1 to9 scale in which “1” indicates “resistant” and “9” indicates“susceptible”.

On2: Ostrinia nubilalis 2nd brood rating. The rating is based on a 1 to9 scale in which “1” indicates “resistant” and “9” indicates“susceptible”.

Relative Maturity: A maturity rating based on regression analysis. Theregression analysis is developed by utilizing check hybrids and theirpreviously established day rating versus actual harvest moistures.Harvest moisture on the hybrid in question is determined and thatmoisture value is inserted into the regression equation to yield arelative maturity.

Root Lodging: Root lodging is the percentage of plants that root lodge.A plant is counted as root lodged if a portion of the plant leans fromthe vertical axis by approximately 30 degrees or more.

Seedling Color: Color of leaves at the 6 to 8 leaf stage.

Seedling Height: Plant height at the 6 to 8 leaf stage.

Seedling Vigor: A visual rating of the amount of vegetative growth on a1 to 9 scale in which the best and worst ratings are “1” and “9”,respectively. The score is taken when the average entry in a trial is atthe fifth leaf stage.

Selection Index: The selection index gives a single measure of hybrid'sworth based on information from multiple traits. One of the traits thatis almost always included is yield. Traits may be weighted according tothe level of importance assigned to them.

Sr: Sphacelotheca reiliana rating. The rating is actual percentinfection.

Stalk-Anthocyanin: A rating of the amount of anthocyanin pigmentation inthe stalk. The stalk is rated 1 to 2 weeks after pollination as absent,basal-weak, basal-strong, weak, or strong.

Stalk-Brace Root Color: The color of the brace roots observed 1 to 2weeks after pollination as green, red, or purple.

Stalk-Diameter: The average diameter of the lowest visible internode ofthe stalk.

Stalk-Ear Height: The average height of the ear when measured from theground to the point of attachment of the ear shank of the top developedear to the stalk.

Stalk-Internode Direction: The direction of the stalk internode observedafter pollination as straight or zigzag.

Stalk-Internode Length: The average length of the internode above theprimary ear.

Stalk Lodging: The percentage of plants that did stalk lodge. Plants arecounted as stalk lodged if the plant is broken over or off below theear.

Stalk-Nodes With Brace Roots: The average number of nodes having braceroots per plant.

Stalk-Plant Height: The average height of the plant when measured fromthe soil to the tip of the tassel.

Stalk-Tillers: The percent of plants that have tillers. A tiller isdefined as a secondary shoot that has developed as a tassel capable ofshedding pollen.

Staygreen: Staygreen is a measure of general plant health near the timeof black layer formation (physiological maturity) and is usuallyrecorded at the time the ear husks of most entries within a trial haveturned a mature color. Scoring is on a 1 to 9 basis in which “1” and “9”are the best and worst score, respectively.

STR: Stalk rot rating. The rating is based on a 1 to 9 scale of severityin which “1” indicates “25% of inoculated internode rotted” and “9”indicates “entire stalk rotted and collapsed”.

SVC: Southeastern Virus Complex (combination of Maize Chlorotic DwarfVirus and Maize Dwarf Mosaic Virus) rating. The numerical rating isbased on a 1 to 9 scale of severity in which “1” indicates “mostresistant” and “9” indicates “most susceptible”.

Tassel-Anther Color: The color of the anthers at 50% pollen shed, whichis scored as green-yellow, yellow, pink, red, or purple.

Tassel-Attitude: The attitude of the tassel after pollination, which isscored as open or compact.

Tassel-Branch Angle: The angle of an average tassel branch to the mainstem of the tassel, which is scored as upright (less than 30 degrees),intermediate (30 to 45 degrees), or lax (greater than 45 degrees).

Tassel-Branch Number: The average number of primary tassel branches.

Tassel-Glume Band: The closed anthocyanin band at the base of the glume,which is scored as present or absent.

Tassel-Glume Color: The color of the glumes at 50% shed, which is scoredas green, red, or purple.

Tassel-Length: The length of the tassel, which is measured from the baseof the bottom tassel branch to the tassel tip.

Tassel-Peduncle Length: The average length of the tassel peduncle, whichis measured from the base of the flag leaf to the base of the bottomtassel branch.

Tassel-Pollen Shed: A visual rating of pollen shed that is determined bytapping the tassel and observing the pollen flow of approximately fiveplants per entry. The rating is based on a 1 to 9 scale in which “9”indicates “sterile” and “1” indicates “most pollen”.

Tassel-Spike Length: The length of the spike, which is measured from thebase of the top tassel branch to the tassel tip.

Test Weight: Weight of the grain in pounds for a given volume (bushel)adjusted to 15.5% moisture.

Yield: Yield of grain at harvest adjusted to 15.5% moisture.

Other Definitions

Allele: Any of one or more alternative forms of a gene locus, all ofwhich relate to one trait or characteristic. In a diploid cell ororganism, the two alleles of a given gene occupy corresponding loci on apair of homologous chromosomes.

Backcrossing: A process in which a breeder repeatedly crosses hybridprogeny back to one of the parents, for example, a first generationhybrid (F₁) with one of the parental genotypes of the F₁ hybrid.

Crossing: The pollination of a female flower of a maize plant, therebyresulting in the production of seed from the flower.

Cross-pollination: Fertilization by the union of two gametes fromdifferent plants.

Diploid: A cell or organism having two sets of chromosomes.

Emasculate: The removal of plant male sex organs or the inactivation ofthe organs with a chemical agent or a cytoplasmic or nuclear geneticfactor conferring male sterility.

F₁ Hybrid: The first generation progeny of the cross of two plants.

Genetic Complement: An aggregate of nucleotide sequences, the expressionof which sequences defines the phenotype in maize plants, or componentsof plants including cells or tissue.

Genotype: The genetic constitution of a cell or organism.

Haploid: A cell or organism having one set of the two sets ofchromosomes in a diploid.

Marker: A readily detectable phenotype, preferably inherited incodominant fashion (both alleles at a locus in a diploid heterozygoteare readily detectable), with no environmental variance component, i.e.,heritability of 1.

Phenotype: The detectable characteristics of a cell or organism, whichcharacteristics are the manifestation of gene expression.

Quantitative Trait Loci (QTL): Genetic loci that contribute, at least inpart, certain numerically representable traits that are usuallycontinuously distributed.

Regeneration: The development of a plant from tissue culture.

Self-pollination: The transfer of pollen from the anther to the stigmaof the same plant.

Single Locus Converted (Conversion) Plant: Plants which are developed bya plant breeding technique called backcrossing wherein essentially allthe morphological and physiological characteristics of an inbred arerecovered in addition to the characteristics conferred by the singlelocus transferred into the inbred via the backcrossing technique.Exemplary procedures for the preparation of such single locusconversions are disclosed in U.S. Pat. No. 7,205,460, the entiredisclosure of which is specifically incorporated herein by reference. Asingle locus may comprise one gene, or in the case of transgenic plants,one or more transgenes integrated into the host genome at a single site(locus). By “essentially all the morphological and physiologicalcharacteristics”, it is meant that all the characteristics of a plantare recovered that are otherwise present when compared in the samegrowing conditions or environment, other than an occasional varianttrait that might arise during backcrossing or direct introduction of atransgene.

Tissue Culture: A composition comprising isolated cells of the same or adifferent type or a collection of such cells organized into parts of aplant.

Transgene: A genetic sequence which has been introduced into the nuclearor chloroplast genome of a maize plant by a genetic transformationtechnique, resulting in a heterologous insertion in the transformedgenome. Transgenes can include genetic sequence from an organism otherthan Zea mays or another Zea species, or can be “cisgenic”, that is tosay, obtained from a Zea mays genome.

Variety Descriptions

Variety ICH72121

Another aspect of this disclosure provides a novel maize hybrid varietydesignated ICH72121. Maize hybrid variety ICH72121 was produced from across of two inbred maize lines, designated “female inbred variety 1”(RR728-18; ATCC Accession number PTA-5628) and “male inbred variety 4”(PHBE2 (ATCC Accession number 97509). The morphological characteristicsof the maize hybrid variety ICH72121 and of the parent lines arepresented in Table 1. Also provided in Table 1 are the morphologicalcharacteristics of a comparable maize hybrid LH195/LH216, grown underthe same conditions.

TABLE 1* Female Inbred 1 RR728- Male 18; Inbred 4 ATCC PHBE2; AccessionATCC number Accession Hybrid PTA- number Variety LH195/ 5628 97509ICH72121 LH216 STALK Plant Height (cm) 186    233 311 295 Ear height(cm) 86    84 118 120 Anthocyanin N/A N/A absent moderate Brace rootcolor N/A N/A green variegated Internode Straight Straight straightstraight direction Internode length 12.2 N/A  21  24 (cm) LEAF Leaf DarkDark Dark Medium color green green green green Leaf length (cm) 86.4  73 90  84 Leaf width (cm) 11     9  11  11 Sheath N/A N/A absent moderateanthocyanin Sheath Moderate Light none light pubescence Marginal wavesFew Few many few Longitudinal Few Few many few creases TASSEL Tassellength (cm) 48    58  60  55 Peduncle length 18    21  22  10 (cm)Branch number  7.3  12   9   8 Anther color Light Yellow yellow yellowgreen Glume color Light Green Light Green with Green green brown marginGlume band Absent Absent absent absent EAR Number of ears 1      1.5   1  1 per stalk Ear position upright pendent horizontal pendent Ear shapeSemi- Cylindrical Semi- Semi- conical conical conical Ear length (cm)14    15  20  20 Ear diameter (cm)  4.2     4.4     5.3   4 Shank length(cm) 10.4   9  12   6 Silk color Light Pink Light Light Green greengreen Husk bract n/a n/a n/a n/a Husk cover (cm) 4    0   6   6 Huskopening Tight Loose Tight Very Husk color, fresh Light Green green tightGreen green Husk color, dry Buff Buff buff buff Cob diameter (cm)  2.5    2.7     2.8     2.2 Cob color Red Red red pink Shelling percent n/an/a n/a n/a KERNEL Kernel row 15.4  16  17  14 number Kernel number 31   32  36  40 per row Row direction Scattered Straight Slightly straightcurved Type Dent dent dent dent Kernel cap color Yellow yellow yellowyellow Kernel side color Yellow yellow yellow yellow Kernel length 10   11  13  11 (depth) (mm) Kernel width  8.5   9   8   8 (mm) Kernelthickness 7    4   4   3 (mm) Endosperm type normal normal normal normalEndosperm color yellow yellow yellow yellow *These are typical values.Values may vary due to environment. Other values that are substantiallyequivalent are within the scope of the invention. “N/A”: not available

Thus, one aspect of the invention provides a novel maize hybrid varietydesignated ICH72121. Maize variety ICH72121 is a hybrid maize varietyproduced from a cross of two inbred maize lines, designated “femaleinbred variety 1” (RR728-18; ATCC Accession number PTA-5628) and “maleinbred variety 4” PHBE2 (ATCC Accession number 97509). One embodimentincludes a maize (Zea mays) plant designated ICH72121, whereinrepresentative seed of the maize variety ICH72121 has been depositedunder ATCC Accession number PTA-126952. Another embodiment includes anessentially homogeneous population of maize plants of the maize varietydesignated ICH72121, for example, an essentially homogeneous populationof maize plants of the maize variety designated ICH72121, whereinrepresentative seed of the maize variety ICH72121 has been depositedunder ATCC Accession number PTA-126952. An embodiment includes a maizeplant of the maize variety designated ICH72121, wherein representativeseed of the maize variety ICH72121 has been deposited under ATCCAccession number PTA-126952, wherein the maize plant is grown from seedthat has been deposited under ATCC Accession number PTA-126952. Yetanother embodiment includes a maize plant that has or is characterizedby all the morphological and physiological characteristics of the maizevariety designated ICH72121.

In an embodiment, the maize plant of the maize variety designatedICH72121 further includes in its genome a transgene introduced by stableor transient transformation, for example, stable or transienttransformation of either the maize plant of the maize variety designatedICH72121 or of one or both of its parent lines. In embodiments, a maizeplant of the maize variety designated ICH72121 further includes in itsgenome a transgene encoding a protein (e.g., an insecticidal protein oran herbicide-resistance protein) or encoding an RNA molecule (e.g., amicroRNA or a double-stranded RNA for RNAi-mediated suppression of atargeted genetic sequence) that provides a desirable trait such asimproved resistance to a pest or pathogen, herbicide resistance,nutritional composition, and/or improved yield.

A related aspect of the invention is a seed that produces the maizeplant of the maize variety designated ICH72121, wherein representativeseed of the maize variety ICH72121 has been deposited under ATCCAccession number PTA-126952. One embodiment includes representative seedof the maize variety ICH72121 that has been deposited under ATCCAccession number PTA-126952. Another embodiment is a seed producedthrough maize breeding that produces the maize plant of the maizevariety designated ICH72121, e.g., a maize plant that has or ischaracterized by all the morphological and physiological characteristicsof maize variety ICH72121. Related aspects include a compositionincluding a seed that produces the maize plant of the maize varietydesignated ICH72121 and a growth medium, such as soil or a synthetic orartificial medium.

A related aspect of the invention is a plant part of the maize plant ofthe maize variety designated ICH72121, wherein representative seed ofthe maize variety ICH72121 has been deposited under ATCC Accessionnumber PTA-126952. In embodiments, the plant part includes or is apollen grain, a silk, a tassel, an anther, an ovule, meristem, root,leaf, shoot, or shoot apex. A specific embodiment is a seed or seedsproduced on the maize plant of the maize variety designated ICH72121.Other embodiments include any part or portion of the maize plant of themaize variety designated ICH72121, or combinations thereof. Relatedaspects further include a protoplast, cell, tissue culture, or callusfrom, or derived from (e.g., using tissue culture techniques) the maizeplant of the maize variety designated ICH72121, as well as a maizeplantlet or plant regenerated from such a protoplast, cell, tissueculture, or callus. Embodiments include a callus or tissue culturecontaining regenerable cells of a maize plant of the maize varietydesignated ICH72121, capable of regenerating plants capable ofexpressing all the physiological and morphological characteristics ofthe maize variety designated ICH72121, and of regenerating plants havingsubstantially the same genotype as other plants of the maize varietydesignated ICH72121; in embodiments, such regenerable cells are obtainedor derived from immature or mature embryos, meristem, immature or maturetassels or silk, microspores, pollen, anthers, leaves, stems, roots orroot tips, silk, flowers, seeds, or other parts or tissue of a plant orseed of the maize variety designated ICH72121.

Related aspects of the invention include a seed of the maize varietydesignated ICH72121, wherein representative seed of the maize varietydesignated ICH72121 has been deposited under ATCC Accession numberPTA-126952. An embodiment is an essentially homogeneous population ofmaize seeds of the maize variety designated ICH72121, whereinrepresentative seed of the maize variety designated ICH72121 has beendeposited under ATCC Accession number PTA-126952. Such an essentiallyhomogeneous population of maize seeds of the maize variety designatedICH72121 can be provided in a container, such as a bag, or can includean essentially homogeneous population of maize seeds planted in a field.A related aspect of the invention includes a method of producing maizeseed, including cultivating the maize plant of the maize varietydesignated ICH72121, wherein representative seed of the maize varietydesignated ICH72121 has been deposited under ATCC Accession numberPTA-126952. A further related aspect of the invention is a method ofproducing a commodity maize product, the method including obtaining themaize plant of the maize variety designated ICH72121, or a part of theplant, and producing the commodity maize product therefrom. In variousembodiments, the commodity maize products include products such as maizegrain; maize starch, carbohydrates, sugars, and fermentation productsthereof; maize seed oil; maize syrup; maize protein; and animal feed orfodder including silage.

Another related aspect of the invention is a maize plant havingessentially all the physiological and morphological characteristics of amaize plant of the maize variety designated ICH72121 (whereinrepresentative seed of the maize variety ICH72121 has been depositedunder ATCC Accession number PTA-126952), and further characterized byhaving at least one additional trait selected from the group consistingof improved abiotic stress tolerance, improved biotic stress tolerance,modified nutritional content, modified metabolism, herbicide resistance,and modified fertility. In this context, “essentially all themorphological and physiological characteristics” refers to all thecharacteristics of a plant of the maize variety designated ICH72121 asprovided in Table 1; it is understood that these characteristics canvary in maize plants that are grown under different conditions or indifferent environments, and therefore for the purpose of comparison of amaize plant's characteristics with those of the disclosed maize varietyICH72121, the maize plant is grown under the same conditions or sameenvironment, and a small amount of variation (generally 5% or less) isacceptable. In embodiments, the additional trait is provided by agenetic locus that is a dominant or recessive allele, which includes,e.g., a naturally occurring maize gene that is introduced into thegenome of a parent of maize variety ICH72121 by backcrossing, or is anatural or induced mutation, or is one or more transgenes introducedthrough genetic transformation techniques. Embodiments of improvedabiotic stress tolerance include improved tolerance to water (drought orflooding), nutrient (nutrient deficiency or excess), temperature (heator cold), or light (insufficient or excessive) stress. Embodiments ofimproved biotic stress tolerance include improved tolerance to crowding,shading, pests or pathogens (e.g., insect, arthropod, or nematode pestsor fungal, bacterial, or viral pathogens). Embodiments of modifiednutritional content include modified protein or amino acid content,modified fatty acid or lipid content, modified carbohydrate content(e.g., waxy starch), modified vitamin or pro-vitamin (e.g., vitamin A orpro-vitamin A or carotenoid) content, or modified lignin, allergen,antifeedant, or toxin (e.g., mycotoxin) content. Embodiments of modifiedmetabolism include modifications to biochemical pathways involved incarbohydrate, protein, or fatty acid metabolism. Embodiments ofherbicide resistance include resistance to herbicides commercially usedin managing maize crops, e.g., glyphosate, ALS inhibitors, and otherherbicides; see, e.g., the information below under the heading“Herbicide Resistance”. Embodiments of modified fertility include maleor female sterility, and fertility restoration. An embodiment is a maizeplant that has essentially all the physiological and morphologicalcharacteristics of a maize plant of the maize variety designatedICH72121 and in addition is characterized by having a cytoplasmic ornuclear factor that is capable of conferring male sterility or otherwisepreventing self-pollination, such as by self-incompatibility. In anembodiment, the trait is cytoplasmically inherited male sterility(“CMS”), a trait passed on to progeny through the female parent andcharacterized by pollen abortion when restorer genes are absent in thenucleus. In the presence of normal cytoplasm or restorer gene(s) in thenucleus, a CMS maize plant produces normal pollen. Thus, a CMS maizeplant can be pollinated by a maintainer version of the same variety,which has a normal cytoplasm but lacks the restorer gene(s) in thenucleus, and continues to be male sterile in the next generation.Alternatively, male fertility of a CMS plant can be restored by arestorer version of the same variety that has the restorer gene(s) inthe nucleus; the resulting progeny plants produce normal pollen.

In embodiments, the at least one additional trait is introduced using atleast one process selected from the group consisting of transformation,genome editing, base editing, epigenetic modification, mutagenesis, andselection of either the maize plant of the maize variety designatedICH72121 or of its parents. Techniques for carrying out these processesare known to one of skill in the art and can be employed singly or incombination in order to effect introduction of the at least oneadditional trait into the maize plant that otherwise has essentially allthe physiological and morphological characteristics of a maize plant ofthe maize variety designated ICH72121. Embodiments of transformationprocesses include transient transformation or stable transformation or acombination of both. Embodiments include a single transformationprocedure (e.g., direct transformation of a plant, a cell or protoplast,a plant part or tissue or seed, or an embryo, germline cell, or pollenof the maize variety designated ICH72121), or multiple transformationprocedures (e.g., transformation of a plant, a cell or protoplast, aplant part or tissue or seed, or an embryo, germline cell, or pollen ofone or both parent lines of the maize variety designated ICH72121, andoptionally also of the maize variety designated ICH72121). Innon-limiting embodiments, for example, the at least one process includesuse of at least one agent selected from a bacterium (e.g., Agrobacteriumsp., Rhizobium sp., Sinorhizobium sp., Mesorhizobium sp., Bradyrhizobiumsp., Azobacter sp., Phyllobacterium sp.) that is capable of transforminga plant cell; a particle or nanoparticle (e.g., nano- or microparticles,nano- or microneedles, nano- or microfibers, and similar materials usedto deliver a polynucleotide or polypeptide reagent in a transformation,genome editing, or base editing process); a recombinant DNA vector(e.g., a DNA polynucleotide or DNA plasmid or viral vector encoding atleast one expression construct for expressing one or morepolynucleotides or polypeptides); a nuclease (e.g., a TAL-effectornuclease, zinc finger nuclease, Cas nuclease, or an Argonaut) or afusion protein or protein complex including one or more of suchnucleases, whether active or inactive, covalently or non-covalentlylinked to another polypeptide domain that provides a desiredfunctionality or polynucleotide(s) encoding the nuclease or fusionprotein or protein complex, and optionally polynucleotides associatedwith the nuclease (such as guide RNAs associated with a Cas nuclease).Nucleases in combination with other proteins or polypeptide domains aredescribed in more detail below under the heading “Nucleases and TheirCombinations”. In embodiments, the at least one additional trait isintroduced using at least one selection step, or multiple selectionsteps, or recurrent selection steps in order to arrive at a maize planthaving the desired additional traits in combination with essentially allthe physiological and morphological characteristics of a maize plant ofthe maize variety designated ICH72121. A selection step can includeexposing a population of maize plants or seedlings (or cells or callusunder tissue culture conditions) to conditions permitting expression ofthe additional trait. For example, selection for herbicide resistancecan include exposing a population of maize plants to an amount ofherbicide that inhibits growth or is toxic, allowing identification andselection of those resistant maize plants that survive treatment and arethen selected for the next breeding cycle. In certain embodiments, aproxy measurement indicative of a desired phenotype or trait is used forselection. For example, selecting for a trait characterized by increasedexpression of an enzyme may be determined by detecting lower levels ofthe enzyme's substrate in the tested plants.

In related embodiments, the at least one additional trait is associatedwith a transgene that is introduced into by backcrossing or genetictransformation of a maize plant designated ICH72121. Embodiments oftransgenes of interest include transgenes encoding polypeptides orpolynucleotides (e.g., miRNAs) that provide a phenotype of interest thatis in addition to essentially all the physiological and morphologicalcharacteristics of a maize plant of the maize variety designatedICH72121. Non-limiting examples of such phenotypes of interest includeherbicide resistance; improved tolerance of abiotic stress (e. g.,tolerance of temperature extremes, drought, or salt) or biotic stress(e. g., resistance to bacterial or fungal pathogens); improvedutilization of nutrients or water; synthesis of new or modified amountsof lipids, carbohydrates, proteins or other chemicals, includingmedicinal compounds; improved flavor or appearance; improvedphotosynthesis; improved storage characteristics (e. g., resistance tobruising, browning, or softening); increased yield; certain alterationsin morphology (e. g., root structure) that do not otherwise change themorphological characteristics of a maize plant of the maize varietydesignated ICH72121; and changes in flowering time. Embodiments ofmodified fertility include male or female sterility, and fertilityrestoration. An embodiment is a maize plant that has essentially all thephysiological and morphological characteristics of a maize plant of themaize variety designated ICH72121 and in addition is characterized byexpressing a transgene that is capable of conferring male sterility,optionally under specific growing conditions, for example a transgenethat expresses both a protein that confers herbicide resistance, and amiRNA or small RNA that prevents expression of the herbicide resistancein male reproductive tissue, resulting in male sterility induced byapplication of the herbicide to the maize plant; see, e.g., the methodsand genetic constructs for providing inducible male sterility in plantsdisclosed in U.S. Pat. Nos. 8,334,430 and 9,139,838, the disclosures ofwhich are incorporated by reference in their entirety herein.

An aspect of the invention provides a method of producing a progenymaize seed derived from maize variety ICH72121, including harvestingseed of a progeny maize plant obtained by crossing a maize plant of themaize variety designated ICH72121, wherein representative seed of themaize variety ICH72121 has been deposited under ATCC Accession numberPTA-126952 with itself or with a second maize plant, thereby producingprogeny maize seed. A related aspect of the invention thus includes theprogeny maize seed produced by this method. 1001341A further aspect ofthe invention provides a method of producing a ICH72121-derived maizeplant, wherein the method including the step of applying to a maizeplant of the maize variety designated ICH72121, wherein representativeseed of the maize variety ICH72121 has been deposited under ATCCAccession number PTA-126952, at least one plant breeding techniqueselected from the group consisting of: selfing, backcrossing,outcrossing, marker-assisted selection or marker-assisted breeding,pedigree breeding, haploid production, doubled haploid production, andtransformation, thereby producing a ICH72121-derived maize plant; arelated aspect of the invention is the ICH72121-derived maize plantproduced by the method. For example, a maize plant of the maize varietydesignated ICH72121 is crossed with a second maize plant of a different,distinct variety to provide a ICH72121-derived progeny plant that has,as either its male or its female parent, the maize variety ICH72121;such a crossing procedure results in the production of seed, which canbe grown into the ICH72121-derived progeny plant. In embodiments, themethod includes (1) the step of applying to a maize plant of the maizevariety designated ICH72121, wherein representative seed of the maizevariety ICH72121 has been deposited under ATCC Accession numberPTA-126952, at least one plant breeding technique selected from thegroup consisting of: selfing, backcrossing, outcrossing, marker-assistedselection or marker-assisted breeding, pedigree breeding, haploidproduction, doubled haploid production, and transformation, therebyproducing a ICH72121-derived maize plant; and further includes (2) thestep of crossing the ICH72121-derived maize plant with itself or with asecond maize plant to produce a seed of a progeny plant of a subsequentgeneration. A related aspect of the invention is the seed produced bythis method, or the progeny plant of a subsequent generation that isgrown from the seed; another related aspect of the invention provides amethod of producing a nucleic acid preparation, including extractingnucleic acids from the seed of a progeny plant of a subsequentgeneration, or from a plant grown from the seed, or from a cell, cellculture, tissue culture, or callus obtained from the seed. In yetfurther embodiments, the method includes (1) the step of applying to amaize plant of the maize variety designated ICH72121, whereinrepresentative seed of the maize variety ICH72121 has been depositedunder ATCC Accession number PTA-126952, at least one plant breedingtechnique selected from the group consisting of: selfing, backcrossing,outcrossing, marker-assisted selection or marker-assisted breeding,pedigree breeding, haploid production, doubled haploid production, andtransformation, thereby producing a ICH72121-derived maize plant; andfurther includes the steps of: (2) crossing the ICH72121-derived maizeplant with itself or with a second maize plant to produce anext-generation seed; (3) growing from the next-generation seed anext-generation progeny plant; and (4) repeating with the resultingnext-generation progeny plant additional crossing steps with itself orwith a different maize plant for at least an additional (1-10)generation to produce a progeny maize plant further derived from maizevariety ICH72121.

Yet another aspect of the invention provides a method of producing anucleic acid preparation, including extracting nucleic acids from amaize plant of the maize variety designated ICH72121, whereinrepresentative seed of the maize variety ICH72121 has been depositedunder ATCC Accession number PTA-126952, or from a cell or part of themaize plant, or from its seed. The extracted nucleic acids are usefulespecially for genetic analysis of the maize plant or its seed. Thus, arelated aspect of the invention provides a method of producing a geneticmarker profile including genotyping nucleic acids extracted from themaize plant designated ICH72121 or from the representative seeddeposited under ATCC Accession number PTA-126952, thereby producing agenetic marker profile. Another related aspect of the invention providesa method of maize breeding including identifying at least one geneticpolymorphism (e.g., a single nucleotide polymorphism (SNP), a specificallele, or one or more mutations) in nucleic acids extracted from themaize plant designated ICH72121 or from the representative seeddeposited under ATCC Accession number PTA-126952, and selecting a maizeplant identified as having the at least one genetic polymorphism,wherein the selected maize plant is used in a maize breeding method toproduce a progeny maize plant; also encompassed by the invention is theprogeny maize plant produced by this method of maize breeding.

A further aspect of the invention provides a method for producing aninbred maize plant including crossing a maize plant of the maize varietydesignated ICH72121, wherein representative seed of the maize varietyICH72121 has been deposited under ATCC Accession number PTA-126952, witha haploid inducer variety to produce haploid seed, and doubling thehaploid seed, thereby producing an inbred maize plant.

Embodiments of the invention provided herein include but are not limitedto the following numbered embodiments.

1. A maize plant of the maize variety designated ICH72121, whereinrepresentative seed of the maize variety ICH72121 has been depositedunder ATCC Accession number PTA-126952.

2. The maize plant of embodiment 1, which is grown from seed that hasbeen deposited under ATCC Accession number PTA-126952.

3. A maize plant having all the physiological and morphologicalcharacteristics of the plant of embodiment 1.

4. The maize plant of embodiment 1, further comprising in its genome atransgene introduced by stable or transient transformation.

5. A seed that produces the maize plant of embodiment 1.

6. A composition comprising the seed of embodiment 5 and a growthmedium.

7. The composition of embodiment 6, wherein the growth medium is soil ora synthetic medium.

8. A plant part of the maize plant of embodiment 1, wherein the plantpart is a pollen grain, a silk, a tassel, an anther, an ovule, meristem,root, leaf, shoot, or shoot apex.

9. A protoplast, cell, tissue culture, or callus from the maize plant ofembodiment 1.

10. A maize plantlet or plant regenerated from the protoplast, cell,tissue culture, or callus of embodiment 9.

11. A maize seed produced on the maize plant of embodiment 1.

12. A seed of maize variety ICH72121, wherein representative seed of themaize variety ICH72121 has been deposited under ATCC Accession numberPTA-126952.

13. A method of producing maize seed, comprising cultivating the maizeplant of embodiment 1 and harvesting seed from the plant.

14. A method of producing a commodity maize product, the methodcomprising obtaining the maize plant of embodiment 1 or a part of theplant, and producing the commodity maize product therefrom.

15. The method of embodiment 14, wherein the commodity maize product isat least one selected from the group of commodity maize productsconsisting of: maize grain; maize starch, carbohydrates, sugars, andfermentation products thereof; maize seed oil; maize syrup; maizeprotein; and animal feed or fodder.

16. A maize plant having essentially all the physiological andmorphological characteristics of the maize plant of embodiment 1 andfurther characterized by having at least one additional trait selectedfrom the group consisting of improved abiotic stress tolerance, improvedbiotic stress tolerance, modified nutritional content, modifiedmetabolism, herbicide resistance, and modified fertility.

17. The maize plant of embodiment 16, wherein the at least oneadditional trait is introduced using at least one process selected fromthe group consisting of transformation, genome editing, base editing,epigenetic modification, mutagenesis, and selection.

18. The maize plant of embodiment 17, wherein the at least one processcomprises use of at least one agent selected from: a bacterium capableof transforming a plant cell; a particle or nanoparticle; a recombinantDNA vector; and a nuclease, or a fusion protein or protein complexincluding a nuclease, and optionally polynucleotides associated with thenuclease.

19. The maize plant of embodiment 16, wherein the at least oneadditional trait is associated with a transgene that is introduced intoby backcrossing or genetic transformation of a maize plant designatedICH72121.

20. A method of producing a progeny maize seed derived from maizevariety ICH72121, comprising harvesting seed of a progeny maize plantobtained by crossing the maize plant of embodiment 1 with itself or witha second maize plant, thereby producing progeny maize seed.

21. The progeny maize seed produced by the method of 20.

22. A method of producing a ICH72121-derived maize plant, the methodcomprising applying to the maize plant of embodiment 1 at least oneplant breeding technique selected from the group consisting of: selfing,backcrossing, outcrossing, marker-assisted selection or breeding,pedigree breeding, haploid production, doubled haploid production, andtransformation, thereby producing a ICH72121-derived maize plant.

23. The ICH72121-derived maize plant produced by the method ofembodiment 22.

24. The method of embodiment 22, further comprising the step of:crossing the ICH72121-derived maize plant with itself or with a secondmaize plant to produce a seed of a progeny plant of a subsequentgeneration.

25. The seed produced by the method of 24, or the progeny plant of asubsequent generation grown from the seed.

26. A method of producing a nucleic acid preparation, comprisingextracting nucleic acids from the seed of embodiment 25, or from a plantgrown from the seed, or from a cell, cell culture, tissue culture, orcallus obtained from the seed.

27. The method of embodiment 22, further comprising the steps of: (a)crossing the ICH72121-derived maize plant with itself or with a secondmaize plant to produce a next-generation seed; (b) growing from thenext-generation seed a next-generation progeny plant; and (c) repeatingwith the resulting next-generation progeny plant additional crossingsteps with itself or with a different maize plant for at least anadditional generation to produce a progeny maize plant further derivedfrom maize variety ICH72121.

28. A method of producing a nucleic acid preparation, comprisingextracting nucleic acids from the maize plant of embodiment 1, or from acell or part of the maize plant, or from its representative seeddeposited under ATCC Accession number PTA-126952.

29. A method of producing a genetic marker profile comprising genotypingnucleic acids extracted from the maize plant designated ICH72121 or fromthe representative seed deposited under ATCC Accession numberPTA-126952, thereby producing a genetic marker profile.

30. A method of maize breeding comprising identifying at least onegenetic polymorphism in nucleic acids extracted from the maize plantdesignated ICH72121 or from the representative seed deposited under ATCCAccession number PTA-126952, and selecting a maize plant identified ashaving the at least one genetic polymorphism, wherein the selected maizeplant is used in a maize breeding method.

31. A maize plant produced by the method of embodiment 30.

32. A method for producing an inbred maize plant comprising crossing themaize plant of embodiment 1 with a haploid inducer variety to producehaploid seed, and doubling the haploid seed, thereby producing an inbredmaize plant.

33. A maize plant having essentially all the physiological andmorphological characteristics of the maize plant of embodiment 1 andfurther characterized by glyphosate herbicide resistance.

DEPOSIT INFORMATION

A deposit of at least 625 seeds of the hybrid maize line ICH72121 ismade on Jan. 5, 2021 with the American Type Culture Collection (ATCC),located at 10801 University Boulevard, Manassas, Va. 20110-2209, UnitedStates of America, and assigned ATCC Accession number PTA-126952. Thedeposits are made pursuant to the terms of the Budapest Treaty, and areintended to meet the requirements of 37 CFR § 1.801-1.809. Access to theseed deposits will be available upon request during the pendency of theapplication to the Commissioner of Patents and Trademarks and personsdetermined by the Commissioner to be entitled thereto. All restrictionsupon availability to the public will be irrevocably removed upongranting of the patent. The deposit will be maintained in the ATCCDepository, which is a public depository, for a period of 30 years, or 5years after the most recent request, or for the enforceable life of thepatent, whichever is longer. The viability of the deposit will be testedand will be replaced if it becomes nonviable during that period. Uponallowance of any claims in the application, Applicant will maintain andwill make this deposit available to the public, pursuant to the BudapestTreaty. Applicant does not waive any infringement of Applicant's rightsgranted under this patent or under the Plant Variety Protection Act (7U.S.C. 2321 et seq.).

RELATED DISCLOSURE

Nucleases and their Combinations

Various aspects of the invention are related to maize plants of themaize hybrid variety ICH72121 as described herein, that have one or moreadditional traits in addition to essentially all the characteristics ofthe variety (e.g., as described, in Table 1). In embodiments, the one ormore additional trait is introduced into a maize plant of the maizehybrid variety ICH72121 (or, alternatively, into one or both parents ofthe variety) with a procedure using one or more nucleases. For example,the genome of a maize plant of the maize hybrid variety ICH72121 cansubjected to a genome editing procedure using a site-specific nucleasethat modifies the genome at a predetermined location. Site-specificnucleases useful for this purpose include Cas nucleases, zinc fingernucleases, TALENs, and Argonautes. In related embodiments, a Casnuclease, zinc finger nuclease, TALEN, or Argonaute is used inconjunction with other functional domains, which can be combined withthe nuclease through a protein fusion or through other covalent ornon-covalent linkages or complexes. The nuclease itself can be normallyfunctional, or can be a deactivated variant; for example, the nucleaseactivity of these nucleic acid targeting systems can be altered so thatthe nuclease binds to but does not cleave the DNA at the predeterminedlocation. Examples of functional domains that can be used in combinationwith an active or deactivated nuclease include transposase domains,integrase domains, recombinase domains, resolvase domains, invertasedomains, protease domains, DNA methyltransferase domains, DNAhydroxylmethylase domains, DNA demethylase domains, histone acetylasedomains, histone deacetylase domains, nuclease domains, repressordomains, activator domains, nuclear-localization signal domains,transcription-regulatory protein (or transcription complex recruiting)domains, cellular uptake activity associated domains, nucleic acidbinding domains, antibody presentation domains, histone modifyingenzymes, recruiter of histone modifying enzymes; inhibitor of histonemodifying enzymes, histone methyltransferases, histone demethylases,histone kinases, histone phosphatases, histone ribosylases, histonederibosylases, histone ubiquitinases, histone deubiquitinases, histonebiotinases and histone tail proteases. Non-limiting examples offunctional domains include a transcriptional activation domain, atranscription repression domain, and an SHH1, SUVH2, or SUVH9polypeptide capable of reducing expression of a target nucleotidesequence via epigenetic modification; see, e. g., U.S. PatentApplication Publication 2016/0017348, incorporated herein by referencein its entirety. Genomic DNA may also be modified via base editing usinga fusion between a catalytically inactive Cas9 (dCas9) is fused to acytidine deaminase which convert cytosine (C) to uridine (U), therebyeffecting a C to T substitution; see Komor et al. (2016) Nature,533:420-424.

Maize Breeding

Embodiments of the invention include maize breeding procedures, such ascrossing two maize parent plants, which are often of distinct geneticbackground or “lines”. Maize crossing typically involves planting,conveniently in pollinating proximity, seeds of a first and secondparent maize plant, which can be of different lines; the resultingseedlings are grown into plants of reproductive maturity, and generallyare prevented from self-pollinating (e.g., by physical emasculation ofthe plant meant to serve as the female parent or by use of a chemicalgametocide). Plants not within pollinating proximity can be pollinatedby transferring pollen from one plant to the other.(Self-incompatibility systems may also be used in some hybrid crops forthe same purpose. Self-incompatible plants still shed viable pollen andcan pollinate plants of other varieties but are incapable of pollinatingthemselves or other plants of the same variety.) Finally, the resultingseed from at least one of the parent maize plants is harvested, thusproviding progeny seed that can be grown to produce a progeny maizeplant.

Tissue Culture

As used herein, the term “tissue culture” indicates a compositioncomprising isolated cells of the same or a different type or acollection of such cells organized into parts of a plant. Exemplarytypes of tissue cultures are protoplasts, calli, and plant cells thatare intact in plants or parts of plants, such as embryos, pollen,flowers, kernels, ears, cobs, leaves, husks, stalks, roots, root tips,anthers, silk, and the like. In one embodiment, the tissue culturecomprises embryos, protoplasts, meristematic cells, pollen, leaves oranthers derived from immature tissues of these plant parts.

Means for preparing and maintaining plant tissue cultures are well knownin the art (U.S. Pat. Nos. 5,538,880 and 5,550,318, each incorporatedherein by reference in their entirety). Examples of processes of tissueculturing and regeneration of maize are described in, for example,European Patent Application Publication No. EP0160390, Green and Rhodes(In: Maize for Biological Research, 367, 1982) and Duncan et al.(Planta, 165:322, 1985), Songstad et al. (Plant Cell Reports, 7:262,1988), Rao et al. (Maize Genetics Cooperation Newsletter, 60, 1986),Conger et al. (Plant Cell Reports, 6:345, 1987), PCT Application WO95/06128, Armstrong and Green (Planta, 164:207, 1985); Gordon-Kamm etal. (The Plant Cell, 2:603, 1990), and U.S. Pat. No. 5,736,369. One typeof tissue culture is tassel/anther culture to produce regeneratedplants. Exemplary methods of microspore culture are disclosed in, forexample, U.S. Pat. Nos. 5,322,789 and 5,445,961, the disclosures ofwhich are specifically incorporated herein by reference.

Haploid and Doubled-Haploid Plants

Uniform lines of new varieties may also be developed by way ofdoubled-haploids. This technique allows the creation of true breedinglines without the need for multiple generations of selfing andselection. In this manner true breeding lines can be produced in aslittle as one generation. Haploid induction systems have been developedfor various plants to produce haploid tissues, plants and seeds. Thehaploid induction system can produce haploid plants from any genotype bycrossing with an inducer line. Inducer lines and methods for obtaininghaploid plants are known in the art.

Haploid embryos may be produced, for example, from microspores, pollen,anther cultures, or ovary cultures. The haploid embryos may then bedoubled autonomously, or by chemical treatments (e.g. colchicinetreatment). Alternatively, haploid embryos may be grown into haploidplants and treated to induce chromosome doubling. In either case,fertile homozygous plants are obtained. Such techniques can be used withmaize plants of the maize hybrid variety ICH72121 as described herein,or with derived or progeny plants thereof, to achieve a homozygous line.

Backcrossing

In the plant breeding technique called backcrossing, essentially all themorphological and physiological characteristics of an original varietyare recovered or retained in the resultant plant obtained by thebackcrossing process, in addition to a genetic locus transferred intothe resultant plant via the backcrossing technique. By essentially allthe morphological and physiological characteristics, it is meant thatall the characteristics of the original plant are recovered or retainedin the resultant plant obtained by the backcrossing process, other thanan occasional variant trait that might arise during backcrossing ordirect introduction of a transgene.

Backcrossing methods can be used with maize plants maize plants of themaize hybrid variety ICH72121 as described herein to improve acharacteristic or introduce a trait of interest. “Backcrossing” refersto the repeated crossing of a hybrid progeny back to one of the hybrid'stwo parental lines, which is termed the recurrent parent as it is usedin several breeding rounds in the backcrossing process. The parentalmaize plant which contributes the locus or loci for the trait is termedthe nonrecurrent or donor parent as it is used only once in thebackcrossing process. The transferred locus can be, e.g., a dominant ora recessive allele, which can include a naturally occurring geneticsequence or can include a transgene that confers the trait of interest.The parental maize plant to which the locus or loci from thenonrecurrent parent are transferred is known as the recurrent parent asit is used for several rounds in the backcrossing process. In a typicalbackcrossing process, the original parent hybrid of interest (recurrentparent) is crossed to a second variety (nonrecurrent parent) thatcarries the genetic locus of interest to be transferred. The resultingprogeny from this cross are then crossed again to the recurrent parentand the process is repeated until a maize plant is obtained whereinessentially all the morphological and physiological characteristics ofthe recurrent parent are recovered in the converted plant, in additionto the transferred locus from the nonrecurrent parent. The backcrossingprocess may be accelerated using genetic markers, such as simplesequence repeats (SSRs), restriction fragment length polymorphisms(RFLPs), amplified fragment length polymorphisms (AFLPs), singlenucleotide polymorphisms (SNPs), and isozyme markers to identify plantswith the greatest genetic complement from the recurrent parent. Incertain cases, direct selection can be used to identify plants in agiven generation that have the transferred locus; for example, plantsthat contain in their genome a transgene that confers herbicideresistance can be identified and selected by application of theherbicide prior to the next backcrossing step, which eliminates plantslacking the transgene.

A plant of any generation in a breeding program can be characterized bygenetic analysis, thus describing its “genetic complement”, that is tosay, the totality of genetic sequences, the expression of which definesthe phenotype of the plant, or of a cell or tissue of the plant. Anaspect of this invention thus provides maize plant cells that have agenetic complement in accordance with that of a maize plant of the maizehybrid variety ICH72121 as described herein, and plants or seedscontaining such cells. A plant's genetic complement may be assessed byobtaining a genetic marker profile from nucleic acids extracted from theplant, and by the expression of phenotypic traits that arecharacteristic of the expression of the genetic complement, e.g.,genetic marker typing profiles. Genetic marker types include SimpleSequence Repeats (SSRs), Simple Sequence Length Polymorphisms (SSLPs),Randomly Amplified Polymorphic DNAs (RAPDs), DNA AmplificationFingerprinting (DAF), Sequence Characterized Amplified Regions (SCARs),Arbitrary Primed Polymerase Chain Reaction (AP-PCR), Amplified FragmentLength Polymorphisms (AFLPs), and Single Nucleotide Polymorphisms(SNPs). Another aspect of the invention provides hybrid geneticcomplements, as represented by maize plant cells, tissues, plants, andseeds, formed by the combination of a haploid genetic complement of amaize plant of the maize hybrid variety ICH72121 as described herein,with a haploid genetic complement of the same or a different variety.Another aspect of the invention provides a maize plant regenerated froma tissue culture that includes a genetic complement of a maize plant ofthe maize hybrid variety ICH72121 as described herein.

Growth Media

Embodiments of the invention include compositions including a seed of amaize variety disclosed herein and a growth medium. Suitable growthmedia are known to those of skill in the art of growing and breedingmaize, and include natural or amended soils and synthetic or artificialgrowth media, for example, as described in U.S. Pat. Nos. 3,932,166,4,707,176, and 4,241,537, the disclosures of which are incorporated byreference in their entirety herein.

Traits and Their Introduction

Useful traits can be introduced by genetic transformation techniques,for example by transformation to stably integrate into a plant's genomea transgene that confers the trait. In some embodiments, a trait isassociated with a specific allele which can be fixed into a plantvariety by breeding techniques such as backcrossing (see the sectionunder the heading “Backcrossing”). In other embodiments, the plant'sgenome can be specifically modified, e.g., by genome editing, baseediting, or epigenetic modification, in order to introduce a desirabletrait that is associated with the modification.

Methods for the genetic transformation of maize are known to those ofskill in the art. For example, methods which have been described for thegenetic transformation of maize include electroporation (U.S. Pat. No.5,384,253), electrotransformation (U.S. Pat. No. 5,371,003),microprojectile bombardment (U.S. Pat. Nos. 5,550,318, 5,736,369 and5,538,880; and PCT Publication WO 95/06128), Agrobacterium-mediatedtransformation (U.S. Pat. No. 5,591,616 and European Patent ApplicationPublication No. EP0672752), direct DNA uptake transformation ofprotoplasts, and silicon carbide fiber-mediated transformation (U.S.Pat. Nos. 5,302,532 and 5,464,765).

Certain embodiments involve methods for specifically modifying a plant'sgenome in order to modify a characteristic in the plant or to introducea trait. Modifying the genome can be carried out at a predeterminedlocus, e.g., by genome editing, base editing, or epigeneticmodification. Examples of such genomic modifications include deletion ofat least one nucleotide, insertion of at least one nucleotide, andreplacements of at least one nucleotide, as well as combinations ofthese. The modification is typically sequence-specific, that is to say,occurring at a pre-selected location in the genome, and can be in codingsequence or in non-coding sequence (e.g., in promoters and otherregulatory sequences, or in intronic sequences) or in both coding andnon-coding sequence. The techniques for such modifications are wellknown in the art and include, e.g., use of sequence-specific nucleasessuch as those used in CRISPR-Cas systems, zinc-finger nucleases (ZFNs),and transcription activator-like effector nucleases (TALENs). Suitablemethods of genomic modification of plants including maize are disclosedin detail in U.S. Patent Application Publication 2019/0352655, which isincorporated by reference in its entirety herein.

Genetic Sequences Associated with Traits

Male Sterility: Examples of genes conferring male sterility includethose disclosed in U.S. Pat. Nos. 3,861,709, 3,710,511, 4,654,465,5,625,132, and 4,727,219, each of the disclosures of which arespecifically incorporated herein by reference in their entirety. Malesterility genes can increase the efficiency with which hybrids are made,in that they eliminate the need to physically emasculate the maize plantused as a female parent in a given cross.

When one desires to employ male-sterility systems with a maize plant, itmay be beneficial to also utilize one or more male-fertility restorergenes. For example, when cytoplasmic male sterility (CMS) is used,hybrid seed production requires three inbred lines: (1) acytoplasmically male-sterile line having a CMS cytoplasm; (2) a fertileinbred with normal cytoplasm, which is isogenic with the CMS line fornuclear genes (“maintainer line”); and (3) a distinct, fertile inbredwith normal cytoplasm, carrying a fertility restoring gene (“restorer”line). The CMS line is propagated by pollination with the maintainerline, with all the progeny being male sterile, as the CMS cytoplasm isderived from the female parent. These male sterile plants can then beefficiently employed as the female parent in hybrid crosses with therestorer line, without the need for physical emasculation of the malereproductive parts of the female parent. The presence of amale-fertility restorer gene results in the production of fully fertileF₁ hybrid progeny. If no restorer gene is present in the male parent,male-sterile hybrids are obtained. Such hybrids are useful when thevegetative tissue of the maize plant is utilized, e.g., for silage, butin most cases, the seeds will be deemed the most valuable portion of thecrop, so fertility of the hybrids in these crops must be restored. Oneaspect of this disclosure thus provides a maize plant of the maizehybrid variety ICH72121 as described herein, comprising a genetic locuscapable of restoring male fertility in an otherwise male-sterile plant.Examples of male-sterility genes and corresponding restorers which couldbe employed with a maize plant of the maize hybrid variety ICH72121 areknown in the art; see, e.g., U.S. Pat. Nos. 5,530,191; 5,689,041;5,741,684; and 5,684,242, the disclosures of which are each specificallyincorporated herein by reference in their entirety.

Herbicide Resistance: Numerous herbicide resistance genes are known andmay be employed with a maize plant disclosed and claimed herein.Embodiments include a gene conferring resistance to an acetolactatesynthase (ALS)-inhibiting herbicide, such as the sulfonylurea herbicidenicosulfuron, that prevents the formation of branched chain amino acidsand inhibits meristem growth. Resistance genes for glyphosate(resistance conferred by mutant 5-enolpyruvylshikimate-3-phosphatesynthase (EPSPS) and aroA genes, respectively) and other phosphonocompounds such as glufosinate (phosphinothricin acetyltransferase (PAT)and Streptomyces hygroscopicus phosphinothricin acetyltransferase (bar)genes) may also be used. See, for example, U.S. Pat. Nos. 4,940,835,6,040,497, and 7,632,985. A DNA molecule encoding a mutant aroA gene canbe obtained under ATCC Accession No. 39256, and the nucleotide sequenceof the mutant gene is disclosed in U.S. Pat. No. 4,769,061. In additionto glyphosate tolerant genes that may be used to make a plant glyphosatetolerant, glyphosate tolerant events may be crossed with the male orfemale inbred to create a glyphosate tolerant inbred, which results inICH72121 glyphosate tolerant, see U.S. Pat. No. 6,040,497 and ATTCAccession Number 209032, 6,762,344, and 7,314,970, all of which areincorporated herein by reference. A hygromycin B phosphotransferase genethat confers resistance to glyphosate is described in Penaloza-Vazquezet al., Plant Cell Reports, 14:482, 1995. European Patent ApplicationPublication No. EP0333033 to Kumada et al., and U.S. Pat. No. 4,975,374to Goodman et al., disclose nucleotide sequences of glutamine synthetasegenes that confer resistance to herbicides such as L-phosphinothricin.The nucleotide sequence of a phosphinothricin acetyltransferase gene isprovided in European Patent Application Publication No. EP0242246.DeGreef et al. (Biotechnology, 7:61, 1989) describe the production oftransgenic plants that express chimeric bar genes coding forphosphinothricin acetyl transferase activity. Exemplary genes conferringresistance to a phenoxy class herbicide haloxyfop and a cyclohexanedioneclass herbicide sethoxydim are the Acct-S1, Acct-S2 and Acct-S3 genes;see Marshall et al., (1992) Theor. Appl. Genet., 83:435. As anon-limiting example, a gene may confer resistance to other exemplaryphenoxy class herbicides that include, but are not limited to,quizalofop-p-ethyl and 2,4-dichlorophenoxyacetic acid (2,4-D). Genes arealso known that confer resistance to herbicides that inhibitphotosynthesis such as, for example, triazine herbicides (psbA and gs+genes) and benzonitrile herbicides (nitrilase gene). As a non-limitingexample, a gene may confer resistance to the exemplary benzonitrileherbicide bromoxynil. Przibila et al. (Plant Cell, 3:169, 1991) describethe transformation of Chlamydomonas with plasmids encoding mutant psbAgenes. Nucleotide sequences for nitrilase genes are disclosed in U.S.Pat. No. 4,810,648 to Stalker, and DNA molecules containing these genesare available under ATCC Accession Nos. 53435, 67441, and 67442. Cloningand expression of DNA coding for a glutathione 5-transferase isdescribed by Hayes et al. (Biochem. J., 285:173, 1992).4-hydroxyphenylpyruvate dioxygenase (HPPD) is a target of theHPPD-inhibiting herbicides, which deplete plant plastoquinone andvitamin E pools. Rippert et al. (Plant Physiol., 134:92, 2004) describesan HPPD-inhibitor resistant tobacco plant that was transformed with ayeast-derived prephenate dehydrogenase (PDH) gene. Protoporphyrinogenoxidase (PPO) is the target of the PPO-inhibitor class of herbicides; aPPO-inhibitor resistant PPO gene was recently identified in Amaranthustuberculatus (Patzoldt et al., PNAS, 103(33):12329, 2006). The herbicidemethyl viologen inhibits CO₂ assimilation. Foyer et al. (Plant Physiol.,109:1047, 1995) describe a plant overexpressing glutathione reductase(GR) that is resistant to methyl viologen treatment. Siminszky(Phytochemistry Reviews, 5:445, 2006) describes plant cytochromeP450-mediated detoxification of multiple, chemically unrelated classesof herbicides. Modified bacterial genes have been successfullydemonstrated to confer resistance to atrazine, a herbicide that binds tothe plastoquinone-binding membrane protein Q_(B) in photosystem II toinhibit electron transport. See, for example, studies by Cheung et al.(PNAS, 85:391, 1988), describing tobacco plants expressing thechloroplast psbA gene from an atrazine-resistant biotype of Amaranthushybridus fused to the regulatory sequences of a nuclear gene, and Wanget al. (Plant Biotech. J., 3:475, 2005), describing transgenic alfalfa,Arabidopsis, and tobacco plants expressing the atzA gene fromPseudomonas sp. that were able to detoxify atrazine. Bayley et al.(Theor. Appl. Genet., 83:645, 1992) describe the creation of2,4-D-resistant transgenic tobacco and cotton plants using the 2,4-Dmonooxygenase gene tfdA from Alcaligenes eutrophus plasmid pJP5. U.S.Patent Application Publication No. 20030135879 describes the isolationof a gene for dicamba monooxygenase (DMO) from Pseudomonas maltophiliathat is involved in the conversion of dicamba to a non-toxic3,6-dichlorosalicylic acid and thus may be used for producing plantstolerant to this herbicide. Other examples of herbicide resistance havebeen described, for instance, in U.S. Pat. Nos. 6,803,501; 6,448,476;6,248,876; 6,225,114; 6,107,549; 5,866,775; 5,804,425; 5,633,435;5,463,175.

Waxy Starch: The waxy characteristic is an example of a recessive trait.In this example, the progeny resulting from the first backcrossgeneration (BC₁) must be grown and selfed. A test is then run on theselfed seed from the BC₁ plant to determine which BC₁ plants carried therecessive gene for the waxy trait. In other recessive traits additionalprogeny testing, for example growing additional generations such as theBC₁S₁, may be required to determine which plants carry the recessivegene.

Disease Resistance: Plant defenses are often activated by specificinteraction between the product of a disease resistance gene (R) in theplant and the product of a corresponding avirulence (Avr) gene in thepathogen. A plant line can be transformed with a cloned resistance geneto engineer plants that are resistant to specific pathogen strains. See,for example, Jones et al., Science, 266:789, 1994, which describes thecloning of the tomato Cf-9 gene for resistance to Cladosporium flavum;Martin et al., Science, 262:1432, 1993, which describes the tomato Ptogene for resistance to Pseudomonas syringae pv.; and Mindrinos et al.,Cell, 78:1089, 1994, which describes the Arabidopsis RPS2 gene forresistance to Pseudomonas syringae.

A viral-invasive protein or a complex toxin derived therefrom may alsobe used for viral disease resistance. For example, the accumulation ofviral coat proteins in transformed plant cells imparts resistance toviral infection and/or disease development effected by the virus fromwhich the coat protein gene is derived, as well as by related viruses.See Beachy et al., (Annu. Rev. Phytopathol., 28:451, 1990). Coatprotein-mediated resistance has been conferred upon transformed plantsagainst alfalfa mosaic virus, cucumber mosaic virus, tobacco streakvirus, potato virus X, potato virus Y, tobacco etch virus, tobaccorattle virus and tobacco mosaic virus. A virus-specific antibody mayalso be used. See, for example, Tavladoraki et al., (Nature, 366:469,1993), who show that transgenic plants expressing recombinant antibodygenes are protected from virus attack. Additional means of inducingwhole-plant resistance to a pathogen include modulation of the systemicacquired resistance (SAR) or pathogenesis related (PR) genes, forexample genes homologous to the Arabidopsis thaliana NIM1/NPR1/SAI1,and/or by increasing salicylic acid production (Ryals et al., PlantCell, 8:1809, 1996).

Logemann et al., (Biotechnology, 10:305, 1992), for example, disclosetransgenic plants expressing a barley ribosome-inactivating gene have anincreased resistance to fungal disease. Plant defensins may be used toprovide resistance to fungal pathogens (Thomma et al., Planta, 216:193,2002). Other examples of fungal disease resistance are provided in U.S.Pat. Nos. 6,653,280; 6,573,361; 6,506,962; 6,316,407; 6,215,048;5,516,671; 5,773,696; 6,121,436; 6,316,407; and 6,506,962.

Insect Resistance: One example of an insect resistance gene includes aBacillus thuringiensis (Bt) protein, a derivative thereof or a syntheticpolypeptide modeled thereon. See, for example, Geiser et al., (Gene,48:109, 1986), who disclose the cloning and nucleotide sequence of a Bt.delta.-endotoxin gene. Moreover, DNA molecules encoding.delta.-endotoxin genes can be purchased from the American Type CultureCollection, Manassas, Va., for example, under ATCC Accession Nos. 40098,67136, 31995 and 31998. Another example is a lectin. See, for example,Van Damme et al., (Plant Molec. Biol., 24:825, 1994), who disclose thenucleotide sequences of several Clivia miniata mannose-binding lectingenes. A vitamin-binding protein may also be used, such as avidin. PCTapplication US93/06487 teaches the use of avidin and avidin homologuesas larvicides against insect pests.

Yet another insect resistance gene is an enzyme inhibitor, for example,a protease or proteinase inhibitor or an amylase inhibitor. See, forexample, Abe et al., (J. Biol. Chem., 262:16793, 1987), which describesthe nucleotide sequence of rice cysteine proteinase inhibitor, Huub etal., (Plant Molec. Biol., 21:985, 1993), which describes the nucleotidesequence of cDNA encoding tobacco proteinase inhibitor I, and Sumitaniet al., (Biosci. Biotech. Biochem., 57:1243, 1993), which describes thenucleotide sequence of Streptomyces nitrosporeus .alpha.-amylaseinhibitor).

An insect-specific hormone or pheromone may also be used. See, forexample, Hammock et al., (Nature, 344:458, 1990), which describesbaculovirus expression of cloned juvenile hormone esterase, aninactivator of juvenile hormone, Gade and Goldsworthy (eds.)(Physiological Systems in Insects, Elsevier Academic Press, Burlington,Mass., 2007), which describes allostatins and their potential use inpest control; and Palli et al., (Vitam. Horm., 73:59, 2005), whichdescribes the use of ecdysteroid and ecdysteroid receptor inagriculture. Additionally, the diuretic hormone receptor (DHR) wasidentified in Price et al., (Insect Mol. Biol., 13:469, 2004) as acandidate target of insecticides.

Still other examples include an insect-specific antibody or animmunotoxin derived therefrom and a developmental-arrestive protein. SeeTaylor et al., (Seventh Intl Symposium on Molecular Plant-MicrobeInteractions, Edinburgh, Scotland, Abstract W97, 1994), who describedenzymatic inactivation in transgenic tobacco via production ofsingle-chain antibody fragments. Nematode resistance has been described,for example, in U.S. Pat. No. 6,228,992 and bacterial disease resistancein U.S. Pat. No. 5,516,671.

Modified Fatty Acid, Phytate, and Carbohydrate Metabolism: Genes may beused conferring modified fatty acid metabolism. For example, stearyl-ACPdesaturase genes may be used. See Knutzon et al., (Proc. Natl. Acad.Sci. USA, 89:2624, 1992). Various fatty acid desaturases have also beendescribed, such as a Saccharomyces cerevisiae OLE1 gene encoding.DELTA.9 fatty acid desaturase, an enzyme which forms themonounsaturated palmitoleic (16:1) and oleic (18:1) fatty acids frompalmitoyl (16:0) or stearoyl (18:0) CoA (McDonough et al., J. Biol.Chem., 267(9):5931-5936, 1992); a gene encoding a stearoyl-acyl carrierprotein delta-9 desaturase from castor (Fox et al., Proc. Natl. Acad.Sci. USA, 90:2486, 1993); .DELTA.6- and .DELTA.12-desaturases from thecyanobacteria Synechocystis responsible for the conversion of linoleicacid (18:2) to gamma-linolenic acid (18:3 gamma) (Reddy et al., PlantMol. Biol., 22:293, 1993); a gene from Arabidopsis thaliana that encodesan omega-3 desaturase (Arondel et al., Science, 258:1353, 1992); plant.DELTA.9 desaturases (PCT Application Publ. No. WO 91/13972) and soybeanand Brassica .DELTA.15 desaturases (European Patent ApplicationPublication No. EP0616644).

Phytate metabolism may also be modified by introduction of aphytase-encoding gene to enhance breakdown of phytate, adding more freephosphate to the transformed plant. For example, see Van Hartingsveldtet al., (Gene, 127:87, 1993), which discloses the nucleotide sequence ofan Aspergillus niger phytase gene. In maize, this, for example, could beaccomplished by cloning and then reintroducing DNA associated with thesingle allele which is responsible for maize mutants characterized bylow levels of phytic acid. See Raboy et al., Plant Physiol., 124:355,1990.

A number of genes are known that may be used to alter carbohydratemetabolism. For example, plants may be transformed with a gene codingfor an enzyme that alters the branching pattern of starch. See Shirozaet al., (J. Bacteriol., 170:810, 1988), which discloses the nucleotidesequence of Streptococcus mutans fructosyltransferase gene, Steinmetz etal., (Mol. Gen. Genet., 20:220, 1985), which discloses the nucleotidesequence of Bacillus subtilis levansucrase gene), Pen et al.,(Biotechnology, 10:292, 1992), which discloses the production oftransgenic plants that express Bacillus licheniformis .alpha.-amylase,Elliot et al., (Plant Molec. Biol., 21:515, 1993), which discloses thenucleotide sequences of tomato invertase genes, Sorgaard et al., (J.Biol. Chem., 268:22480, 1993), which discloses site-directed mutagenesisof barley .alpha.-amylase gene, and Fisher et al., (Plant Physiol.,102:1045, 1993) which discloses maize endosperm starch branching enzymeII. The Z10 gene encoding a 10 kD zein storage protein from maize mayalso be used to alter the quantities of 10 kD zein in the cells relativeto other components (Kirihara et al., Gene, 71:359, 1988). U.S. Pat. No.6,930,225 describes maize cellulose synthase genes and methods of usethereof.

Resistance to Abiotic Stress: Abiotic stress includes dehydration orother osmotic stress, salinity, high or low light intensity, high or lowtemperatures, submergence, exposure to heavy metals, and oxidativestress. Delta-pyrroline-5-carboxylate synthetase (PSCS) from mothbeanhas been used to provide protection against general osmotic stressMannitol-1-phosphate dehydrogenase (mt1D) from E. coli has been used toprovide protection against drought and salinity. Choline oxidase (codAfrom Arthrobactor globiformis) can protect against cold and salt. E.coli choline dehydrogenase (betA) provides protection against salt.Additional protection from cold can be provided by omega-3-fatty aciddesaturase (fad7) from Arabidopsis thaliana. Trehalose-6-phosphatesynthase and levan sucrase (SacB) from yeast and Bacillus subtilis,respectively, can provide protection against drought (summarized fromAnnex II Genetic Engineering for Abiotic Stress Tolerance in Plants,Consultative Group On International Agricultural Research TechnicalAdvisory Committee). Overexpression of superoxide dismutase can be usedto protect against superoxides, as described in U.S. Pat. No. 5,538,878to Thomas et al.

Additional Traits: Additional traits can be introduced into the maizevariety of the present invention. A non-limiting example of such a traitis a coding sequence which decreases RNA and/or protein levels. Thedecreased RNA and/or protein levels may be achieved through RNAimethods, such as those described in U.S. Pat. No. 6,506,559 to Fire etal.

Another trait that may find use with the maize variety of the inventionis a sequence which allows for site-specific recombination. Examples ofsuch sequences include the FRT sequence used with the FLP recombinase(Zhu and Sadowski, J. Biol. Chem., 270:23044, 1995); and the LOXsequence used with CRE recombinase (Sauer, Mol. Cell. Biol., 7:2087,1987). The recombinase genes can be encoded at any location within thegenome of the maize plant, and are active in the hemizygous state.

It may also be desirable to make maize plants more tolerant to or moreeasily transformed with Agrobacterium tumefaciens. Expression of p53 andiap, two baculovirus cell-death suppressor genes, inhibited tissuenecrosis and DNA cleavage. Additional targets can include plant-encodedproteins that interact with the Agrobacterium Vir genes; enzymesinvolved in plant cell wall formation; and histones, histoneacetyltransferases and histone deacetylases (reviewed in Gelvin,Microbiology & Mol. Biol. Reviews, 67:16, 2003).

In addition to the modification of oil, fatty acid or phytate contentdescribed above, it may additionally be beneficial to modify the amountsor levels of other compounds. For example, the amount or composition ofantioxidants can be altered. See, for example, U.S. Pat. Nos. 6,787,618and 7,154,029 and International Patent Application Publication No. WO00/68393, which disclose the manipulation of antioxidant levels, andInternational Patent Application. Publication No. WO 03/082899, whichdiscloses the manipulation of an antioxidant biosynthetic pathway.

Additionally, seed amino acid content may be manipulated. U.S. Pat. No.5,850,016 and International Patent Application Publication No. WO99/40209 disclose the alteration of the amino acid compositions ofseeds. U.S. Pat. Nos. 6,080,913 and 6,127,600 disclose methods ofincreasing accumulation of essential amino acids in seeds. U.S. Pat. No.5,559,223 describes synthetic storage proteins in which the levels ofessential amino acids can be manipulated. International PatentApplication Publication No. WO 99/29882 discloses methods for alteringamino acid content of proteins. International Patent ApplicationPublication No. WO 98/20133 describes proteins with enhanced levels ofessential amino acids. International Patent Application Publication No.WO 98/56935 and U.S. Pat. Nos. 6,346,403, 6,441,274 and 6,664,445disclose plant amino acid biosynthetic enzymes. International PatentApplication Publication No. WO 98/45458 describes synthetic seedproteins having a higher percentage of essential amino acids thanwild-type. U.S. Pat. No. 5,633,436 discloses plants comprising a highercontent of sulfur-containing amino acids; U.S. Pat. No. 5,885,801discloses plants comprising a high threonine content; U.S. Pat. No.5,885,802 discloses plants comprising a high methionine content; U.S.Pat. No. 5,912,414 discloses plants comprising a high methioninecontent; U.S. Pat. No. 5,990,389 discloses plants comprising a highlysine content; U.S. Pat. No. 6,459,019 discloses plants comprising anincreased lysine and threonine content; International Patent ApplicationPublication No. WO 98/42831 discloses plants comprising a high lysinecontent; International Patent Application Publication No. WO 96/01905discloses plants comprising a high threonine content; and InternationalPatent Application Publication No. WO 95/15392 discloses plantscomprising a high lysine content.

All cited patents and patent publications referred to in thisapplication are incorporated herein by reference in their entirety. Allof the materials and methods disclosed and claimed herein can be madeand used without undue experimentation as instructed by the abovedisclosure and illustrated by the examples. Although the materials andmethods of this invention have been described in terms of embodimentsand illustrative examples, it will be apparent to those of skill in theart that substitutions and variations can be applied to the materialsand methods described herein without departing from the concept, spirit,and scope of the invention. All such similar substitutes andmodifications apparent to those skilled in the art are deemed to bewithin the spirit, scope, and concept of the invention as encompassed bythe embodiments of the inventions recited herein and the specificationand appended claims.

What is claimed is:
 1. A maize plant of the maize variety designatedICH72121, wherein representative seed of the maize variety ICH72121 hasbeen deposited under ATCC Accession number PTA-126952.
 2. The maizeplant of claim 1, which is grown from seed that has been deposited underATCC Accession number PTA-126952.
 3. A maize plant having all thephysiological and morphological characteristics of the plant of claim 1.4. The maize plant of claim 1, further comprising in its genome atransgene introduced by stable transformation.
 5. A seed that producesthe maize plant of claim
 1. 6. A composition comprising the seed ofclaim 5 and a growth medium.
 7. The composition of claim 6, wherein thegrowth medium is soil or a synthetic medium.
 8. A plant part of themaize plant of claim 1, wherein the plant part is a pollen grain, asilk, a tassel, an anther, an ovule, meristem, root, leaf, shoot, orshoot apex.
 9. A protoplast, cell, tissue culture, or callus from themaize plant of claim
 1. 10. A maize plantlet or plant regenerated fromthe , cell, tissue culture, or callus of claim
 9. 11. A maize grainproduced on the maize plant of claim
 1. 12. A seed of maize varietyICH72121, wherein representative seed of the maize variety ICH72121 hasbeen deposited under ATCC Accession number PTA-126952.
 13. A method ofproducing maize seed, comprising cultivating the maize plant of claim 1and harvesting seed from the plant.
 14. A method of producing acommodity maize product, the method comprising obtaining the maize plantof claim 1 or a part of the plant, and producing the commodity maizeproduct therefrom.
 15. The maize plant of claim 1, wherein the maizeplant has at least one additional trait introduced using at least oneprocess selected from the group consisting of transformation, genomeediting, epigenetic modification, and mutagenesis.
 16. The maize plantof claim 15, wherein the at least one process comprises use of at leastone agent selected from the group consisting of: a bacterium capable oftransforming a plant cell; a particle or nanoparticle; a recombinant DNAvector; and a nuclease, or a fusion protein or protein complex includinga nuclease, and optionally polynucleotides associated with the nuclease.17. The maize plant of claim 1, wherein the maize plant has at least oneadditional trait associated with a transgene that is introduced into bybackcrossing or genetic transformation of a maize plant designatedICH72121.
 18. A method of producing a progeny maize seed derived frommaize variety ICH72121, comprising harvesting seed of a progeny maizeplant obtained by crossing the maize plant of claim 1 with itself orwith a second maize plant, thereby producing progeny maize seed.